The present invention relates to mobile RF terminals required to conduct bi-directional communications with a base station via a satellite link, and more particularly to a method and apparatus for identifying which one of a plurality of mobile terminals is causing interference with one or more satellites orbiting adjacent a target satellite.
With mobile RF terminals located on mobile platforms such as aircraft, cruise ships and other moving platforms, communicating with a ground station via a transponded satellite, there is always the remote possibility, in spite of the safeguards that may be built into the mobile terminal, that the terminal may fail in an unanticipated manner. In such event, there is the possibility that the mobile terminal may cause interference with other satellites orbiting in the geo arc adjacent to the target satellite with which the mobile terminal had been communicating.
It is also recognized that Fixed Services Satellite (FSS) operators may have difficulty in locating interference from VSAT (Very Small Aperture Terminal) systems that consist of thousands of unsophisticated terminals at remote sites.
Therefore, there exists a need for a ground station in communication with a plurality of mobile terminals via a transponded satellite to be able to quickly identify a malfunctioning mobile terminal which is causing interference with non-target satellites and to quickly resolve the interference incident.
The present invention relates to a system and method for determining which one of a plurality of mobile terminals is causing an interference situation with one or more non-target satellites orbiting adjacent a target satellite with which the mobile terminals are communicating. The system and method involves having each mobile terminal periodically transmit, via the transponded satellite, signals to a base station, such as a ground-based network operations center (NOC), indicating various operational parameters of the mobile terminal as well as operational parameters of the mobile platform (e.g., aircraft) on which the terminal is located. These various operational parameters include the position of the mobile platform (i.e., longitude and latitude), attitude information (e.g., heading, pitch and roll of an aircraft), instances of aircraft establishing communications with the NOC, data rate and changes in the transmissions from each mobile terminal, power control commands being sent by the NOC to the mobile terminals, as well as any operating anomalies detected by the NOC.
All of the above information/events are logged (i.e., recorded) by the NOC in real time, as well as the time of day that each event occurs. The result is a real time xe2x80x9ctime linexe2x80x9d of transmissions/events that the NOC has logged and which can be quickly reviewed in a matter of seconds when needed.
If the NOC learns that interference is occurring with a non-target satellite, the above-described time line of transmissions/events can be quickly reviewed to determine that particular transmission/event that occurred just prior to the time that the interference began to occur. The NOC can then quickly determine which particular mobile terminal has caused the interference and transmit the appropriate commands to the interfering mobile terminal to eliminate the interference or to instruct the mobile terminal to stop transmitting completely. The above process can be carried out in seconds by the NOC as soon the NOC learns that an interference condition has arisen.